Polimorfismos de DNA mitocondrial en poblaciones antiguas de la cuenca mediterránea.

Resumo

The origins of the European populations have been extensively studied from different disciplines. It is thought that ancient demic expansions, like those occurred after the Late Glacial Maximum or during the neolithic diffussion from Middle East to Europe. The possibility to recover DNA from past populations offers an unique opportunity to test in situ these hypothesis. It were analyzed 197 teeth and bones from 115 individuals and 17 different archaeological sites from Middle East and the Iberian Peninsula . It was possible to recover 244pb-mitochondrial DNA sequences from 35 different individuals. They were compared to sequences from 38 European, African and Middle Eastern present-day populations. Phylogenetic reconstructions from Reynolds genetic distance showed that ancient samples clustered together, clearly separated from extant populations. However, phylogenetic reconstructions based on ancient and modern haplotypes showed that ancient mitochondrial haplotypes are related to extant ones. Haplotype and haplogroup frequencies in the ancient samples from Middle East and the Iberian Peninsula are clearly different from those present nowadays in the same geographical regions. Haplogroups related to neolithic expansion to Europe J, U3, W and X- are absent in ancient middle eastern sample. There are two possible explanations to this fact. First, it could be possible that the ancient samples analyzed wont be representative of the Middle Eastern populations that expanded the neolithic. Second, it could be also possible that those haplogroups wont have been introduzed in Europe with demic expansions associated to neolithic. At this work it were also examined several technical aspects related to the obtention of genuine ancient DNA and the influence of different variables in DNA preservation. "